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Old September 18, 2023, 03:53 PM   #1
Idaho 45 Vaquero
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.38-56 Winchester in a Contender

Howdy,

I have been a Thompson Contender fan for a little while and already have two frames, 7 pistols barrels, and one carbine barrel. It is addicting. I also reload and have a "thing" for the most unusual calibers.

I was on Bullberry Barrels Custom website and noticed they offer 38-56 Winchester in their order lineup, which I happen to accidentally have reloading dies for. The brass can be made out of 45-70 from what I understand. Of course this was a blackpowder era cartridge mainly for lever actions.

However, I am wondering, what kind of capability this cartridge in a Thompson Contender rifle might have? I could load smokeless and jacketed bullets? Maybe, have something similar in power to 35 Bullberry or .375 Winchester? Any idea how to determine the pressure so I could keep it safe in a Contender?

What do you all think? Anybody done anything like this?
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Old September 18, 2023, 05:26 PM   #2
Jim Watson
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Google, man, google
https://castboolits.gunloads.com/sho...with-smokeless
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Old September 18, 2023, 05:44 PM   #3
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I read that forum. It seems they are trying to load to around blackpowder velocity as to not erode old barrels. A contender would have a new modern barrel.

I noticed it was mentioned in that forum a load of 28 grains of IMR 3031 for 38-56 and a 265gr cast, which is the same powder charge for cowboy loads for the 38-55. From what I've googled IMR 3031 seems like a place to start. More modern loads for 38-55 seem to be around 33gr. or 34gr. compressed, but a 38-56 has more case capacity.

Hmmm.....I wonder what 35 grains of IMR-3031 with a 250gr. jacketed pointed bullet would do?
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Old September 18, 2023, 06:18 PM   #4
ligonierbill
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CAUTION: The following post includes load data generated by calculation in QuickLOAD (QL) or Gordon Reloading Tool (GRT) software is based on particular powder lots, the assumption the primer is as mild as possible, and assumptions about component, chamber and gun geometry that may not correspond well to what you have. Such data should be approached by working up from published starting loads. USE THIS DATA AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL, nor QL's author or distributor nor GRT's author assumes any liability for any damage or injury resulting from use of this information or information derived from it.

You might check Cowboy Action forums. Your round was offered in the Winchester 1886, and there are still some around. Mike Venturino published loads, but the only smokeless he used was Accurate 5744. QL does include 38-56 with a listed MAP of 1,400 bar (20,305 psi). I plugged in your 35 gr IMR-3031 with a 250 gr Sierra SPBT COL 2.6. Out of a 20" barrel, the prediction is about 1,800 fps at a bit over 25,000.

Please note the warning. I do play with old rounds and sometimes use QL as one piece of information, but in doing so I realize I'm definitely off the pavement. Good luck, but go slow and keep your goals modest.
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Old September 19, 2023, 11:40 AM   #5
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My old Cartridges of the World shows a load of 36gr IMR 3031 pushing a 255gr slug to 1830fps. Barrel length not given, pressure not given.

.38-56 dimensions given in that book show the case base and rim to be 0.006" smaller than the .45-70 case.

Considering that the given specs are assumed to be max, and most brass is slightly under that (for reliable chambering) you might be able to size .45-70 down to .38-56, but I don not know if it is easily possible, or practical. IF the case base can be sized down to fit, you'd still need to turn the .45-70 rim down a bit, and also trim for length.

Since you already have .38-56 dies, you might try sizing a .45-70 case to see the results. I would recommend having a stuck case extractor kit ready, though. What concerns me is the size difference of the solid head.

IF it works, great, you have a brass source. But, if not, then what??

A word of caution, the dimensions given in my old (1972)Cartridges of the World may NOT be correct. I found a difference in data in .45-70 head and rim size between that book and a 2013 Hornady manual of .004 and .006".

Further research to corroborate or disprove the specs given in the old book would be needed BEFORE proceeding with dies, tools, etc.

Might be a good idea to get with Bullberry and find out what specs they cut their .38-56 chambers to.

Good Luck!
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Old September 19, 2023, 11:49 AM   #6
Jim Watson
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.40-65 of the same 1886 family of cartridges is readily formed from .45-70.
More I cannot say.
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Old September 20, 2023, 01:54 PM   #7
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Thanks All.

This is all very theoretical until I order a barrel. And there is a long list of barrels tugging at my Contender addiction. So it might not happen.

But interesting thought, an old obsolete cartridge might have quite an enhanced ability chambered in a strong modern rifle. The Contender max is around 45,000psi, maybe could reach 250gr. going 2000fps and still be safe??? Got me thinking about what it could do in an Encore or Ruger No.1 too.

As said, this is all theoretical for now. And I understand playing with ballistics is a game that requires caution.
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Old September 20, 2023, 02:19 PM   #8
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Quote:
The Contender max is around 45,000psi,
This depends on what you consider "max" and safety.

Remember that generally, when speaking about "max pressures" we are talking about WORKING pressure limits, not the physical safety boundaries of the gun steel & design itself.

Working limits are set for a safe place with continuous, use and operation. Think of them like the redline on a tachometer. Run under or even at it, all day, no problems. Exceed it slightly and briefly, no problems. Go too far or for too long, problems, up to and including component failure.

Considering it was originally a black powder round, and smokeless powder handloads, (still safe in a BP rifle) pushed the 255gr from the 1300fps (BP speed) up to the 1800fps range I don't see why you, handloading for YOUR gun couldn't get 2000 out of a Contender without dangerous pressure. Out of a Contender carbine, almost certainly. From a 10" or 14" tube? you'd have to see what happens.
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